A family of Microsoft word processing software products for creating web, email, and print documents.
The chances of editing a scanned document in PDF format are slim. What you would have is a graphic. You may be able to open the original PDF document in Word, but what changes you may make are limited depending on how the original PDF was created. PDF is not designed to be edited.
If you scan to JPG or PNG format you could use graphic editing software to make changes.